摘要:

AbstractBicyclo[3.2.1]octa‐2,6‐diene‐ax‐ and ‐eq‐4‐carboxylic acids (IIIa) have been preparedviaKnoevenagel condensation of bicyclo[3.1.0]hex‐2‐ene‐6‐endo‐carbaldehyde (Ia). Synthesis and properties are reported ofendo‐4‐t‐butoxy‐bicyclo[3.1.0]hex‐2‐ene‐6‐endo‐carbaldehyde (Ib). This aldehyde has been converted toendo‐8‐t‐butoxybicyclo[3.2.1]octa‐2,6‐diene (IIIb) and toendo‐8‐t‐butoxybicyclo[3.2.1]octa‐2,6‐diene‐ax‐ and ‐eq‐4‐carboxylic acids

ISSN:0165-0513    

DOI:10.1002/recl.19690880702

出版商:WILEY‐VCH Verlag    

年代:1969

数据来源: WILEY

摘要:

AbstractThe liquid phase hydrogenation of 1,3,5‐tri‐t‐butylbenzene (I) over palladium, platinum and rhodium has been studied.Cis‐1,3,5‐tri‐t‐butylcyclohexene (II) is shown to be an important intermediate in the hydrogenation of I. The rates of hydrogenation of I, II, and some other alkylsubstituted benzenes and cyclohexenes over palladium and platinum have been compared.The isomeric 1,3,5‐tri‐t‐butylcyclohexanes and 1,3,5‐tri‐t‐butylcyclohexenes have been prepared. The conformation ofcis, trans‐

ISSN:0165-0513    

DOI:10.1002/recl.19690880703

出版商:WILEY‐VCH Verlag    

年代:1969

数据来源: WILEY

摘要:

AbstractIntermolecular hydrogen bonding between phenol and a series of monomeric andtrans‐dimericC‐nitroso compounds has been studied by IR and PMR spectroscopy.The rather small OH stretching frequency shifts Δvfor monomericC‐nitroso compounds indicate a weak “ground state” basicity for the NO group. For fivep‐substituted nitrosobenzenes Δvvalues are correlated by σ+substituent constants.Trans‐dimericC‐nitroso compounds form stronger hydrogen bonds than the corresponding monomers, resulting in a shift of the monomer‐trans‐‐dimer equilibrium upon addition of a

ISSN:0165-0513    

DOI:10.1002/recl.19690880704

出版商:WILEY‐VCH Verlag    

年代:1969

数据来源: WILEY

摘要:

AbstractProducts have been isolated and identified from two photochemical reactions of 9,9′‐bifluorenylidene (I). The photo‐oxidation of I yields 9‐fluorenone, the cyclodehydrogenation fluoreno(1,9a,9‐a,b)fluoranthene together with the reduced form of I, 9,9′

ISSN:0165-0513    

DOI:10.1002/recl.19690880705

出版商:WILEY‐VCH Verlag    

年代:1969

数据来源: WILEY

ISSN:0165-0513    

DOI:10.1002/recl.19690880706

出版商:WILEY‐VCH Verlag    

年代:1969

数据来源: WILEY

摘要:

Abstractl‐ and D‐2‐amino‐6‐dimethylamino‐4‐hexynoic acid were synthesized, starting fromL‐ andD‐propargylglycine obtained by enzymatic resolution ofDL‐N‐ace‐tylpropargylglycine with acylase I. The dimethylaminomethylene group was introduced through a Mannich reaction of theN‐acetylpropargylglycine ethyl esters with formaldehyde and dimethylamine (Scheme A). By reaction ofL‐ andD‐2‐amino‐6‐chloro‐4‐hexynoic acid, prepared by enzymatic resolution of theDL‐N‐acetyl compound, with dimethylamine identical end products were ob

ISSN:0165-0513    

DOI:10.1002/recl.19690880707

出版商:WILEY‐VCH Verlag    

年代:1969

数据来源: WILEY

摘要:

AbstractMössbauer measurements for some compounds of the formula Fe(ligand)6(ClO4)2are reported. The values for the chemical shift and the quadrupole splitting are compared with literature data. For several ligands the chemical shift is compared with the spectrochemical parameters Dq and β. No simple relationship between the chemical shift and either Dq, or β, or Dq/β could be obser

ISSN:0165-0513    

DOI:10.1002/recl.19690880708

出版商:WILEY‐VCH Verlag    

年代:1969

数据来源: WILEY

摘要:

AbstractThe sulfonation ofo‐ andm‐xylene in concentrated aqueous sulfuric acid has been investigated. Rates and isomer distributions have been measured. The results are discussed in terms of two sulfonating mechanisms. The isomer distributions at 25.0° for the mechanism with H2S2O7as sulfonating entity are 45.1 ± 0.4% 3‐ and 54.9 ± 0.4% 4‐substitution foro‐xylene, and 14.5 ± 0.6% 2‐, 84.3 ± 0.6% 4‐ and 1.2 ± 0.2% 5‐substitution form‐xylene. For the mechanism with H3SO4+as sulfonating entity these data are 6.5 ± 0.9%, 3‐ and 93.5 ± 0.9% 4‐substitution witho‐xylene, and 0.5 ± 0.2% 2‐, 98.9 ± 0.4% 4‐ and 0.6 ± 0.2% 5‐substitution withm‐xylene. The smaller degree of 3‐substitution witho‐xylene for the H2S2O7‐ as compared with the H3SO4+‐ mechanism is mainly due to a difference in entropy of activation. The former mechanism encounters more steric hindrance than the latter on substitutionorthoto a methyl group. The experimental partial rate factors for the three isomeric xylenes for the two sulfonation mechanisms differ by less than a factor of 4 from those calculated on the basis of additivity of substituent effects with the exception of the 2‐position ofm‐xylene, for sulfonation by the entity H3SO4+, and of the 2‐ and 4

ISSN:0165-0513    

DOI:10.1002/recl.19690880709

出版商:WILEY‐VCH Verlag    

年代:1969

数据来源: WILEY

摘要:

AbstractTreatment of 1‐(α‐hydroxyalkyl‐1‐methoxyallenes CH2CC(OCH3)C(OH)R1R2(I, with R1and R2H, alkyl or (CH2)5‐) with a catalytic amount ofp‐toluenesulfonic acid in tetrahydrofuran gives 3,8‐dimethoxy‐1,6‐dioxacyclodeca‐3,8‐dienes (VI) in low to moderate yield.The same treatment of 1‐(β‐hydroxyethyl)‐1‐methylthioallenes RCH = C=C(SCH3)CH2CH2OH (IX, with R = H orn‐C3H7) produces 4‐methylthio‐5,6‐dihydro‐2H‐pyrans (X and XI) in good yields.Addition of gaseous hydrogen chlorid

ISSN:0165-0513    

DOI:10.1002/recl.19690880710

出版商:WILEY‐VCH Verlag    

年代:1969

数据来源: WILEY

摘要:

AbstractOxidative coupling of 4‐methylcatechol with phloroacetophenone and methylphloroacetophenone leads to 6‐acetyl‐4,4a‐dihydro‐7,9‐dihydroxy‐4a‐methyl‐2,3‐dibenzofurandione (Ie) and 6‐acetyl‐4,4a‐dihydro‐7,9‐dihydroxy‐4a,8‐dimethyl‐2,3‐dibenzofurandione (IIe), respectively.The same type of compound is formed when using 3,5‐dimethyl, 3,4‐di‐methyl‐ or 3,4,6‐trimethyl‐catechols instead of 4‐methylcatechol. However, 3,4‐dimethyl‐ and 3,4,6‐trimethyl‐catechols give mainl

ISSN:0165-0513    

DOI:10.1002/recl.19690880711

出版商:WILEY‐VCH Verlag    

年代:1969

数据来源: WILEY